If you have an old broken NES or SEGA Genesis controller and you're looking for a fun project to bring it back to life, consider adding an mp3 player like retro gaming forum System 11 user burgerkingdiamond (BKD) did.

For this project BKD first applied retr0bright to restore the yellowed plastic, then opened the controlled and added in a $20 Coby mp3 player he scored from eBay. He added the headphone jack in the hole for the controller cord, added the USB port from the player, cut a hole in the controller for the mp3 player display, and wired the controller buttons to control everything.